model.py

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

def connect_to_db(app, db_uri="postgresql:///goals"):
    """Connect the database to our Flask app."""

    # Configure to use our PostgreSQL database
    app.config['SQLALCHEMY_DATABASE_URI'] = db_uri
    app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
    # app.config['SQLALCHEMY_ECHO'] = True
    db.app = app
    db.init_app(app)


class User(db.Model):
    """Users in the system"""

    __tablename__ = 'users'

    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    email = db.Column(db.String(100), unique=True, nullable=False)
    password = db.Column(db.String(50), nullable=False)

    goals = db.relationship('Goal', 
                             backref='users')
    def __repr__(self):
        return f'<User id={self.id} email={self.email}>'

class Goal(db.Model):
    """Goals added to the database by users"""

    __tablename__ = 'goals'

    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
    description = db.Column(db.Text)


    def __repr__(self):
        return f'<Goal id={self.id}>'


def init_app():
    from flask import Flask
    app = Flask(__name__)

    connect_to_db(app)
    print("Connected to DB")


if __name__ == "__main__":
    # As a convenience, if we run this module interactively, it will leave
    # you in a state of being able to work with the database directly.

    from server import app
    init_app()